1 /* 2 * Copyright (C) 2007 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.io; 18 19 import static com.google.common.base.Preconditions.checkNotNull; 20 21 import java.io.FilterInputStream; 22 import java.io.IOException; 23 import java.io.InputStream; 24 import java.util.Random; 25 26 /** Returns a random portion of the requested bytes on each call. */ 27 class RandomAmountInputStream extends FilterInputStream { 28 private final Random random; 29 RandomAmountInputStream(InputStream in, Random random)30 public RandomAmountInputStream(InputStream in, Random random) { 31 super(checkNotNull(in)); 32 this.random = checkNotNull(random); 33 } 34 read(byte[] b, int off, int len)35 @Override public int read(byte[] b, int off, int len) throws IOException { 36 return super.read(b, off, random.nextInt(len) + 1); 37 } 38 } 39